Since the last report, continued improvements in analytical technology have extended the lower practical limit for internal amino acid sequence analysis of proteins separated by gel electrophoresis to the vicinity of 50 pmol. This has allowed analysis of several novel proteins and has facilitated analysis of proteins previously under study. Sufficient sequence information was obtained for the cyclic GMP- inhibited phosphodiesterase described in the last report to allow cloning and expression. Approximately 300 residues of unique sequence have been obtained for a novel neuronal calmodulin binding protein. Though sufficient sequence has been obtained to account for over 60% of the protein's primary structure, no significant homology with other mammalian proteins has been detected. A protein demonstrating UV irradiation-induced DNA binding activity has been sequenced, allowing isolation of the full-length cDNA. During studies related to purification of adenylyl cyclase (Z01-BB- 07004-03), several proteins binding to forskolin affinity supports were observed. Three of these have been identified as the cytoskeletal proteins tubulin, actin, and clathrin. Several proteins binding the putative second messenger Ap5A were also identified by sequence analysis as various glycolytic enzymes, indicating the possibility of a novel level of regulation of these processes. The general utility of these techniques has also been used to support efforts within CBER to identify the particular components within allergenic materials that are responsible for their untoward effects with the eventual goal of allowing better standardization of allergenic products. Primary sequence from apple and wheat antigens that react with sera from allergic patients has identified them as previously undescribed proteins.